1. Field of the Invention
The present invention relates to low profile pneumatic radial tires having an aspect ratio of 0.3 to 0.6. Particularly, the invention relates to the configuration and construction of passenger car tires, suitable for use in super high speed running, at axially opposite side regions of treads thereof.
2. Related Art Statement
It is a conventional practice that the configuration and construction of low profile tires having small aspect ratios, which tires are suitable for use in super high speed running, do not greatly differ from those of tires having relatively greater aspect ratios.
That is, the thickness of a tread rubber from a tread surface to an outermost layer of a belt is substantially the same over the entire width of the tread, and the belt comprises two belt layers which are composed of metal cords intersecting with one another between the belt layers and which are arranged corresponding to a ground contact width of the tread. A carcass is turned up from axially inside to outside of the tire.
However, when the tire having the above-mentioned structure and configuration is run at super high speeds, the center region of the tread is more likely to wear. The tread wears in a flat fashion, that is, the worn surface of the tread is a surface substantially in parallel with a rotary axis of the tire. As a result, the amount of tread wear at axially opposite side regions is extremely smaller as compared with that at the tread central region.
This is considered to be caused because the tire of such a type is used under a range of small loads during rotation, centrifugal force during rotation under load is large, and thus the central region of the tread having a greater mass is likely to project axially outwardly from the opposite side region.
After a middle stage wear, the tire of this type has serious problems such as separation at opposite edges of the belt layers, and further burst-out at sidewall portions take place to lower durability of the tire.